The present invention generally relates to excavating apparatus and, in a preferred embodiment thereof, more particularly provides improved apparatus for removably attaching a wear member, such as an excavating tooth adapter, to the lip portion of an excavating device such as a bucket, dipper or the like.
Large excavating buckets, dippers or the like are typically provided with a series of earth-cutting teeth which are each formed from two primary parts--a relatively large adapter and a relatively small replaceable point. The adapter has a base portion which is connectable to the forward lower lip of the bucket, and a nose portion onto which the tooth point is removably secured by a suitable connecting pin or other connecting structure. Compared to that of the adapter, the useful life of the point is rather short--the adapter typically lasting through five or more point replacements until the tremendous earth forces and abrasion to which the adapter is subjected necessitates its replacement.
Various structures have been previously proposed for removably securing adapters, and other wear members such as wear shrouds, to excavating lip structures. For example, in U.S. Pat. No. 5,713,145 to Ruvang a wear shroud having a generally C-shaped cross section is removably secured to the front edge of an excavating bucket lip by first placing the front lip edge in the interior of the wear shroud so that the top and bottom legs of the shroud respectively extend along the top and bottom sides of the lip. A rear end portion of the top shroud leg is then removably secured, using a J-bolt, to a base structure welded to the top side of the lip. A nut threaded onto the J-bolt at the rear end of the top shroud leg and facing the welded base structure prevents the forward removal of the installed wear shroud from the bucket lip. To permit such removal, it is necessary to gain access to the rear end of the top shroud leg and rearwardly remove the nut from the J-bolt.
This technique securely attaches the wear shroud to a front edge portion of the lip with only the top leg of the shroud being anchored, via the top side lip weld base, to the lip. When a larger wear member, such as an excavating tooth adapter, is to be removably attached to the lip it is typically desirable to additionally anchor a rear end portion of the bottom wear member leg to the lip to increase the strength of wear member attachment. using this J-bolt attachment technique on both of the top and bottom wear member legs would, of course substantially increase the strength with which the wear member was removably held on the bucket lip. However, to decouple the bottom wear member leg from the lip it would be necessary to gain access to the rear end of the bottom wear member leg which is positioned a substantial distance from the front lip edge along the underside of the lip. This requirement to access the rear end of the bottom wear member leg beneath the typically massive bucket lip would undesirably make its decoupling from the bucket lip an awkward, difficult and potentially dangerous task.
It can thus be seen that a need exists for apparatus for removably securing the rear ends of both of the upper and lower leg portions of a wear member, such as an excavating tooth adapter, to a bucket lip in a manner permitting the decoupling of the lower leg from the lip without having to access the rear end of the lower leg. It is to this need that the present invention is directed.